Turbocompressor impelling fuel recycle in fuel cell power plant

Abstract

A fuel cell power plant ( 7, 7 a ) has a stack ( 8 ) fed hydrogen-rich fuel gas from a source ( 14, 14 a ) with fuel recycle ( 30, 34 ) through a compressor ( 20 ) of a turbocompressor ( 19 ) having a turbine ( 17, 17 a ) driven either by high pressure hydrogen ( 14 ) or air exhaust ( 41 ).

1. A fuel cell power plant, comprising:
 a plurality of fuel cells, each cell having an anode, a cathode and a proton exchange membrane disposed between the anode and the cathode; 
 fuel reactant flow fields on an anode side of said membrane and oxidant reactant flow fields on a cathode side of said membrane, each of said flow fields having an inlet and an outlet; 
 a source of hydrogen-rich fuel gas, said hydrogen-rich fuel gas being applied to said fuel reactant flow fields; 
 a source providing oxidant reactant gas to said oxidant flow fields; 
 an impeller connected to at least some of said fuel flow field outlets for pumping partially depleted fuel to at least some of said fuel flow field inlets; 
 said impeller comprising a compressor of a turbocompressor, a turbine of which is driven by said hydrogen-rich fuel gas. 
 
   
   
     2. A fuel cell power plant according to  claim 1 , wherein:
 said impeller is connected between all of said fuel flow field outlets and all of said fuel flow field inlets. 
 
   
   
     3. A fuel cell power plant, comprising:
 a plurality of fuel cells, each cell having an anode, a cathode and a proton exchange membrane disposed between the anode and the cathode; 
 fuel reactant flow fields on an anode side of said membrane and oxidant reactant flow fields on a cathode side of said membrane, each of said flow fields having an inlet and an outlet; 
 a source of hydrogen-rich fuel gas, said hydrogen-rich fuel gas being applied to said fuel reactant flow fields; 
 a source providing oxidant reactant gas to said oxidant flow fields; 
 an impeller connected to at least some of said fuel flow field outlets for pumping partially depleted fuel to at least some of said fuel flow field inlets; 
 said impeller comprising a compressor of a turbocompressor, a turbine of which is driven by oxidant reactant gas flowing from said oxidant flow field outlets. 
 
   
   
     4. A fuel cell power plant according to  claim 3 , wherein: said source providing oxidant reactant gas is an air pump. 
   
   
     5. A fuel cell power plant according to  claim 3  wherein:
 said source providing oxidant reactant gas is an air blower. 
 
   
   
     6. A fuel cell power plant according to  claim 3 , wherein:
 said impeller is connected between all of said fuel flow field outlets and all of said fuel flow field inlets. 
 
   
   
     7. A fuel cell power plant, comprising:
 a plurality of fuel cells, each cell having an anode, a cathode and a proton exchange membrane disposed between the anode and the cathode; 
 fuel reactant flow fields on an anode side of said membrane and oxidant reactant flow fields on a cathode side of said membrane, each of said flow fields having an inlet and an outlet; 
 a source of hydrogen-rich fuel gas, said hydrogen-rich fuel gas being applied to said fuel reactant flow fields; 
 a source providing oxidant reactant gas to said oxidant flow fields; 
 an impeller connected to at least some of said fuel flow field outlets for pumping partially depleted fuel to at least some of said fuel flow field inlets; 
 said impeller comprising a compressor of a turbocompressor, a turbine of which is driven directly by said hydrogen-rich fuel gas.